AIKEN, S.C. - Recently, EM workers for the first time removed equipment contaminated with plutonium once used to power deep space missions from a building known as 235-F, marking a milestone in reducing risk at the Savannah River Site (SRS) facility.
The two-story, blast-resistant, windowless, reinforced concrete 235-F has been inactive for more than 25 years. One section of the building, known as the Plutonium Fuel Form (PuFF) Facility, was used to make fuel spheres and pellets out of plutonium (pu)-238. The pu-238 powered deep space missions, such as the Galileo space probe to Jupiter launched from the Space Shuttle Atlantis in October 1989.
“This material removal marks a huge milestone in the multi-year process to reduce the risk and clean up the PuFF Facility cells," 235-F Project Manager Jeff Hasty said. “We started planning for removal in 2012 and have been preparing the cells since then. Work completed so far in the facility includes removing fixed combustibles, upgrading the fire detection system, de-energizing unneeded electrical circuits, draining and cleaning shield windows after their partial disassembly, and installing light sources."
Inside the PuFF Facility are nine cells of thick concrete walls with shielded windows. Employees who worked there remained outside the cells as they handled hazardous materials with remote manipulators. Material entered the facility in Cell 1 and traveled through the other cells to be made into spheres and pellets.
"This project is extremely challenging," Hasty said. “Along with the amount of material involved, we are also working in very tight spaces with limited accessibility. Because of the way the spheres and pellets were made, the pu-238 was left in some cells as a very fine particulate dust that is easily disturbed. Every move we make will need to be slow, deliberate, and precise."
The Savannah River National Laboratory (SRNL) worked with the 235-F Risk Reduction Team to determine that an estimated 1,500 grams of pu-238 remain within the shielded cells. EM workers practiced cleanup work in a mock-up of 235-F.
SRNL is using existing technology and developing new tools to locate and remove or affix the pu-238 to ensure it will not become mobile during decontamination activities. Any pu-238 and tools containing pu-238 will be safely stored for eventual packaging and shipment to EM’s Waste Isolation Pilot Plant in New Mexico for disposal.
“Cell 1 is the most contaminated cell and we expect to be working in it for the rest of 2018 and 2019," Hasty said. "However, in this type of situation, ensuring the safety of our workers is the highest priority, so we will work slowly and purposefully."
The material set to be removed includes wires and manipulator handles. Operators will work remotely as they pass the items through the cells for removal. The cells will then be vacuumed and otherwise cleaned to remove the leftover plutonium.
“We are committed to reducing risk at SRS, and to removing as much material from the facility as practical," Hasty added.
Source: U.S. Dept. of Energy, Office of Environmental Management
